437 lines
16 KiB
PHP
437 lines
16 KiB
PHP
<?php
|
|
/**
|
|
* Class used internally by Text_Diff to actually compute the diffs.
|
|
*
|
|
* This class is implemented using native PHP code.
|
|
*
|
|
* The algorithm used here is mostly lifted from the perl module
|
|
* Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
|
|
* http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
|
|
*
|
|
* More ideas are taken from: http://www.ics.uci.edu/~eppstein/161/960229.html
|
|
*
|
|
* Some ideas (and a bit of code) are taken from analyze.c, of GNU
|
|
* diffutils-2.7, which can be found at:
|
|
* ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
|
|
*
|
|
* Some ideas (subdivision by NCHUNKS > 2, and some optimizations) are from
|
|
* Geoffrey T. Dairiki <dairiki@dairiki.org>. The original PHP version of this
|
|
* code was written by him, and is used/adapted with his permission.
|
|
*
|
|
* Copyright 2004-2010 The Horde Project (http://www.horde.org/)
|
|
*
|
|
* See the enclosed file COPYING for license information (LGPL). If you did
|
|
* not receive this file, see http://opensource.org/licenses/lgpl-license.php.
|
|
*
|
|
* @author Geoffrey T. Dairiki <dairiki@dairiki.org>
|
|
* @package Text_Diff
|
|
*/
|
|
class Text_Diff_Engine_native {
|
|
|
|
function diff($from_lines, $to_lines)
|
|
{
|
|
array_walk($from_lines, array('Text_Diff', 'trimNewlines'));
|
|
array_walk($to_lines, array('Text_Diff', 'trimNewlines'));
|
|
|
|
$n_from = count($from_lines);
|
|
$n_to = count($to_lines);
|
|
|
|
$this->xchanged = $this->ychanged = array();
|
|
$this->xv = $this->yv = array();
|
|
$this->xind = $this->yind = array();
|
|
unset($this->seq);
|
|
unset($this->in_seq);
|
|
unset($this->lcs);
|
|
|
|
// Skip leading common lines.
|
|
for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
|
|
if ($from_lines[$skip] !== $to_lines[$skip]) {
|
|
break;
|
|
}
|
|
$this->xchanged[$skip] = $this->ychanged[$skip] = false;
|
|
}
|
|
|
|
// Skip trailing common lines.
|
|
$xi = $n_from; $yi = $n_to;
|
|
for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
|
|
if ($from_lines[$xi] !== $to_lines[$yi]) {
|
|
break;
|
|
}
|
|
$this->xchanged[$xi] = $this->ychanged[$yi] = false;
|
|
}
|
|
|
|
// Ignore lines which do not exist in both files.
|
|
for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
|
|
$xhash[$from_lines[$xi]] = 1;
|
|
}
|
|
for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
|
|
$line = $to_lines[$yi];
|
|
if (($this->ychanged[$yi] = empty($xhash[$line]))) {
|
|
continue;
|
|
}
|
|
$yhash[$line] = 1;
|
|
$this->yv[] = $line;
|
|
$this->yind[] = $yi;
|
|
}
|
|
for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
|
|
$line = $from_lines[$xi];
|
|
if (($this->xchanged[$xi] = empty($yhash[$line]))) {
|
|
continue;
|
|
}
|
|
$this->xv[] = $line;
|
|
$this->xind[] = $xi;
|
|
}
|
|
|
|
// Find the LCS.
|
|
$this->_compareseq(0, count($this->xv), 0, count($this->yv));
|
|
|
|
// Merge edits when possible.
|
|
$this->_shiftBoundaries($from_lines, $this->xchanged, $this->ychanged);
|
|
$this->_shiftBoundaries($to_lines, $this->ychanged, $this->xchanged);
|
|
|
|
// Compute the edit operations.
|
|
$edits = array();
|
|
$xi = $yi = 0;
|
|
while ($xi < $n_from || $yi < $n_to) {
|
|
assert($yi < $n_to || $this->xchanged[$xi]);
|
|
assert($xi < $n_from || $this->ychanged[$yi]);
|
|
|
|
// Skip matching "snake".
|
|
$copy = array();
|
|
while ($xi < $n_from && $yi < $n_to
|
|
&& !$this->xchanged[$xi] && !$this->ychanged[$yi]) {
|
|
$copy[] = $from_lines[$xi++];
|
|
++$yi;
|
|
}
|
|
if ($copy) {
|
|
$edits[] = new Text_Diff_Op_copy($copy);
|
|
}
|
|
|
|
// Find deletes & adds.
|
|
$delete = array();
|
|
while ($xi < $n_from && $this->xchanged[$xi]) {
|
|
$delete[] = $from_lines[$xi++];
|
|
}
|
|
|
|
$add = array();
|
|
while ($yi < $n_to && $this->ychanged[$yi]) {
|
|
$add[] = $to_lines[$yi++];
|
|
}
|
|
|
|
if ($delete && $add) {
|
|
$edits[] = new Text_Diff_Op_change($delete, $add);
|
|
} elseif ($delete) {
|
|
$edits[] = new Text_Diff_Op_delete($delete);
|
|
} elseif ($add) {
|
|
$edits[] = new Text_Diff_Op_add($add);
|
|
}
|
|
}
|
|
|
|
return $edits;
|
|
}
|
|
|
|
/**
|
|
* Divides the Largest Common Subsequence (LCS) of the sequences (XOFF,
|
|
* XLIM) and (YOFF, YLIM) into NCHUNKS approximately equally sized
|
|
* segments.
|
|
*
|
|
* Returns (LCS, PTS). LCS is the length of the LCS. PTS is an array of
|
|
* NCHUNKS+1 (X, Y) indexes giving the diving points between sub
|
|
* sequences. The first sub-sequence is contained in (X0, X1), (Y0, Y1),
|
|
* the second in (X1, X2), (Y1, Y2) and so on. Note that (X0, Y0) ==
|
|
* (XOFF, YOFF) and (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
|
|
*
|
|
* This function assumes that the first lines of the specified portions of
|
|
* the two files do not match, and likewise that the last lines do not
|
|
* match. The caller must trim matching lines from the beginning and end
|
|
* of the portions it is going to specify.
|
|
*/
|
|
function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks)
|
|
{
|
|
$flip = false;
|
|
|
|
if ($xlim - $xoff > $ylim - $yoff) {
|
|
/* Things seems faster (I'm not sure I understand why) when the
|
|
* shortest sequence is in X. */
|
|
$flip = true;
|
|
list ($xoff, $xlim, $yoff, $ylim)
|
|
= array($yoff, $ylim, $xoff, $xlim);
|
|
}
|
|
|
|
if ($flip) {
|
|
for ($i = $ylim - 1; $i >= $yoff; $i--) {
|
|
$ymatches[$this->xv[$i]][] = $i;
|
|
}
|
|
} else {
|
|
for ($i = $ylim - 1; $i >= $yoff; $i--) {
|
|
$ymatches[$this->yv[$i]][] = $i;
|
|
}
|
|
}
|
|
|
|
$this->lcs = 0;
|
|
$this->seq[0]= $yoff - 1;
|
|
$this->in_seq = array();
|
|
$ymids[0] = array();
|
|
|
|
$numer = $xlim - $xoff + $nchunks - 1;
|
|
$x = $xoff;
|
|
for ($chunk = 0; $chunk < $nchunks; $chunk++) {
|
|
if ($chunk > 0) {
|
|
for ($i = 0; $i <= $this->lcs; $i++) {
|
|
$ymids[$i][$chunk - 1] = $this->seq[$i];
|
|
}
|
|
}
|
|
|
|
$x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $chunk) / $nchunks);
|
|
for (; $x < $x1; $x++) {
|
|
$line = $flip ? $this->yv[$x] : $this->xv[$x];
|
|
if (empty($ymatches[$line])) {
|
|
continue;
|
|
}
|
|
$matches = $ymatches[$line];
|
|
reset($matches);
|
|
while (list(, $y) = each($matches)) {
|
|
if (empty($this->in_seq[$y])) {
|
|
$k = $this->_lcsPos($y);
|
|
assert($k > 0);
|
|
$ymids[$k] = $ymids[$k - 1];
|
|
break;
|
|
}
|
|
}
|
|
while (list(, $y) = each($matches)) {
|
|
if ($y > $this->seq[$k - 1]) {
|
|
assert($y <= $this->seq[$k]);
|
|
/* Optimization: this is a common case: next match is
|
|
* just replacing previous match. */
|
|
$this->in_seq[$this->seq[$k]] = false;
|
|
$this->seq[$k] = $y;
|
|
$this->in_seq[$y] = 1;
|
|
} elseif (empty($this->in_seq[$y])) {
|
|
$k = $this->_lcsPos($y);
|
|
assert($k > 0);
|
|
$ymids[$k] = $ymids[$k - 1];
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
$seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
|
|
$ymid = $ymids[$this->lcs];
|
|
for ($n = 0; $n < $nchunks - 1; $n++) {
|
|
$x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
|
|
$y1 = $ymid[$n] + 1;
|
|
$seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
|
|
}
|
|
$seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
|
|
|
|
return array($this->lcs, $seps);
|
|
}
|
|
|
|
function _lcsPos($ypos)
|
|
{
|
|
$end = $this->lcs;
|
|
if ($end == 0 || $ypos > $this->seq[$end]) {
|
|
$this->seq[++$this->lcs] = $ypos;
|
|
$this->in_seq[$ypos] = 1;
|
|
return $this->lcs;
|
|
}
|
|
|
|
$beg = 1;
|
|
while ($beg < $end) {
|
|
$mid = (int)(($beg + $end) / 2);
|
|
if ($ypos > $this->seq[$mid]) {
|
|
$beg = $mid + 1;
|
|
} else {
|
|
$end = $mid;
|
|
}
|
|
}
|
|
|
|
assert($ypos != $this->seq[$end]);
|
|
|
|
$this->in_seq[$this->seq[$end]] = false;
|
|
$this->seq[$end] = $ypos;
|
|
$this->in_seq[$ypos] = 1;
|
|
return $end;
|
|
}
|
|
|
|
/**
|
|
* Finds LCS of two sequences.
|
|
*
|
|
* The results are recorded in the vectors $this->{x,y}changed[], by
|
|
* storing a 1 in the element for each line that is an insertion or
|
|
* deletion (ie. is not in the LCS).
|
|
*
|
|
* The subsequence of file 0 is (XOFF, XLIM) and likewise for file 1.
|
|
*
|
|
* Note that XLIM, YLIM are exclusive bounds. All line numbers are
|
|
* origin-0 and discarded lines are not counted.
|
|
*/
|
|
function _compareseq ($xoff, $xlim, $yoff, $ylim)
|
|
{
|
|
/* Slide down the bottom initial diagonal. */
|
|
while ($xoff < $xlim && $yoff < $ylim
|
|
&& $this->xv[$xoff] == $this->yv[$yoff]) {
|
|
++$xoff;
|
|
++$yoff;
|
|
}
|
|
|
|
/* Slide up the top initial diagonal. */
|
|
while ($xlim > $xoff && $ylim > $yoff
|
|
&& $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
|
|
--$xlim;
|
|
--$ylim;
|
|
}
|
|
|
|
if ($xoff == $xlim || $yoff == $ylim) {
|
|
$lcs = 0;
|
|
} else {
|
|
/* This is ad hoc but seems to work well. $nchunks =
|
|
* sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5); $nchunks =
|
|
* max(2,min(8,(int)$nchunks)); */
|
|
$nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
|
|
list($lcs, $seps)
|
|
= $this->_diag($xoff, $xlim, $yoff, $ylim, $nchunks);
|
|
}
|
|
|
|
if ($lcs == 0) {
|
|
/* X and Y sequences have no common subsequence: mark all
|
|
* changed. */
|
|
while ($yoff < $ylim) {
|
|
$this->ychanged[$this->yind[$yoff++]] = 1;
|
|
}
|
|
while ($xoff < $xlim) {
|
|
$this->xchanged[$this->xind[$xoff++]] = 1;
|
|
}
|
|
} else {
|
|
/* Use the partitions to split this problem into subproblems. */
|
|
reset($seps);
|
|
$pt1 = $seps[0];
|
|
while ($pt2 = next($seps)) {
|
|
$this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
|
|
$pt1 = $pt2;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Adjusts inserts/deletes of identical lines to join changes as much as
|
|
* possible.
|
|
*
|
|
* We do something when a run of changed lines include a line at one end
|
|
* and has an excluded, identical line at the other. We are free to
|
|
* choose which identical line is included. `compareseq' usually chooses
|
|
* the one at the beginning, but usually it is cleaner to consider the
|
|
* following identical line to be the "change".
|
|
*
|
|
* This is extracted verbatim from analyze.c (GNU diffutils-2.7).
|
|
*/
|
|
function _shiftBoundaries($lines, &$changed, $other_changed)
|
|
{
|
|
$i = 0;
|
|
$j = 0;
|
|
|
|
assert('count($lines) == count($changed)');
|
|
$len = count($lines);
|
|
$other_len = count($other_changed);
|
|
|
|
while (1) {
|
|
/* Scan forward to find the beginning of another run of
|
|
* changes. Also keep track of the corresponding point in the
|
|
* other file.
|
|
*
|
|
* Throughout this code, $i and $j are adjusted together so that
|
|
* the first $i elements of $changed and the first $j elements of
|
|
* $other_changed both contain the same number of zeros (unchanged
|
|
* lines).
|
|
*
|
|
* Furthermore, $j is always kept so that $j == $other_len or
|
|
* $other_changed[$j] == false. */
|
|
while ($j < $other_len && $other_changed[$j]) {
|
|
$j++;
|
|
}
|
|
|
|
while ($i < $len && ! $changed[$i]) {
|
|
assert('$j < $other_len && ! $other_changed[$j]');
|
|
$i++; $j++;
|
|
while ($j < $other_len && $other_changed[$j]) {
|
|
$j++;
|
|
}
|
|
}
|
|
|
|
if ($i == $len) {
|
|
break;
|
|
}
|
|
|
|
$start = $i;
|
|
|
|
/* Find the end of this run of changes. */
|
|
while (++$i < $len && $changed[$i]) {
|
|
continue;
|
|
}
|
|
|
|
do {
|
|
/* Record the length of this run of changes, so that we can
|
|
* later determine whether the run has grown. */
|
|
$runlength = $i - $start;
|
|
|
|
/* Move the changed region back, so long as the previous
|
|
* unchanged line matches the last changed one. This merges
|
|
* with previous changed regions. */
|
|
while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
|
|
$changed[--$start] = 1;
|
|
$changed[--$i] = false;
|
|
while ($start > 0 && $changed[$start - 1]) {
|
|
$start--;
|
|
}
|
|
assert('$j > 0');
|
|
while ($other_changed[--$j]) {
|
|
continue;
|
|
}
|
|
assert('$j >= 0 && !$other_changed[$j]');
|
|
}
|
|
|
|
/* Set CORRESPONDING to the end of the changed run, at the
|
|
* last point where it corresponds to a changed run in the
|
|
* other file. CORRESPONDING == LEN means no such point has
|
|
* been found. */
|
|
$corresponding = $j < $other_len ? $i : $len;
|
|
|
|
/* Move the changed region forward, so long as the first
|
|
* changed line matches the following unchanged one. This
|
|
* merges with following changed regions. Do this second, so
|
|
* that if there are no merges, the changed region is moved
|
|
* forward as far as possible. */
|
|
while ($i < $len && $lines[$start] == $lines[$i]) {
|
|
$changed[$start++] = false;
|
|
$changed[$i++] = 1;
|
|
while ($i < $len && $changed[$i]) {
|
|
$i++;
|
|
}
|
|
|
|
assert('$j < $other_len && ! $other_changed[$j]');
|
|
$j++;
|
|
if ($j < $other_len && $other_changed[$j]) {
|
|
$corresponding = $i;
|
|
while ($j < $other_len && $other_changed[$j]) {
|
|
$j++;
|
|
}
|
|
}
|
|
}
|
|
} while ($runlength != $i - $start);
|
|
|
|
/* If possible, move the fully-merged run of changes back to a
|
|
* corresponding run in the other file. */
|
|
while ($corresponding < $i) {
|
|
$changed[--$start] = 1;
|
|
$changed[--$i] = 0;
|
|
assert('$j > 0');
|
|
while ($other_changed[--$j]) {
|
|
continue;
|
|
}
|
|
assert('$j >= 0 && !$other_changed[$j]');
|
|
}
|
|
}
|
|
}
|
|
|
|
}
|